Slow Internet ?

I have a 640kb DSL line, which due to where I live is all I can get at the moment. This was working fine until suddenly on one Friday is suddenly slowed down completely.

My router says I am connecting at a downstream connection speed of 800kbps and an upstream connection of 320kbps. However, I cannot surf the internet as it is too slow. I cannot carry out a speed test as it times out before it's done anything.

I have had the telephone company out who supply my connection and they say that the exchange is too small and the reason that it has slowed down is due to the fact that more people are on my line and they are unable to increase it.

Bearing in mind that my router says I am connecting at the above speeds, is it a problem with my ISP and should I change ISP's or will I have the same proplem if I change. Any help would be much appreciated.